The TAB report provides a broad overview of the current state of knowledge and debate regarding many of the issues associated with the expansion and modernisation of electricity grids. In addition to the scale of the expansion and modernisation requirements, this includes the identification of modern technologies and operating methods for electricity grids, as well as a description of their current stage of development and the associated research and development needs. As focusing solely on technological aspects would be insufficient, a range of other relevant influencing factors and subject areas were examined. On the one hand, this concerns economic aspects, including the costs and benefits of deploying certain technologies, such as so-called smart meters. On the other hand, however, the study also examines the implications of these developments, particularly data protection issues in modern electricity grids, which are increasingly merging with information networks (smart grids), as well as potential impacts on the environment and public health. Last but not least, the study addresses issues of public participation and acceptance regarding the construction of power lines, which have recently gained enormous significance.